Joint for high tension cables



Nov. 26, 1940.

L. L. PHILLIPS JOINT FOR HIGH TENSION CABLES Filed Dec, 5. 1938 2Sheets-Sheet l Inventor: L ,eter LMP-)bil HPS.

Hi Attorney.

NOV. 26, 1940. L L PHlLLlPS 2,222,718

JOINT FOR HIGH TENSION CABLES Filed Dec. 5, 1938 2 Sheetssheet 2METAL/25D Figli. METAL/25o Inventor: Lester* L ,.Fhl lips,

His Att ormey.

Patented Nov. 26, 1940 PATENT OFFICE 2,222,718 JOINT FOR HIGH TENSINCABLES Lester L. Phillips, Pittsfield, Mass., assignor to GeneralElectric Company, a corporation of New York Application December 3,i938, Serial No. 248,30@b

I8 Claims.

My invention relates vto high tension cables of the single conductortype containing liquid insulation, such as degasied oil, undersuperatmospheric pressure. To limit the head pres- 5 sure where thecable is on a slope and also to limit the escape of liquid in case of aleak in the enclosing sheath, stop-joints are provided which segregatethe cable into determined lengths or sections as regards the liquidwithout,

l however, interrupting the ow of current.

These stop-joints are necessarily of considerable size, are complex inconstruction and relatively expensive. As commonly constructed, the costof installing them is a material item of eX- pense due to the largeamount of hand Work which has to be done in the field by the cablesplicers. In particular, one of the items of expense is the wrapping byhand of the metal parts designed to operate at high potential withinsulating tape. As a specific illustration of which I have knowledge, astop-joint of prior normal construction for a 138,000 volt cablerequires approximately 1400 to 1500 yards of one inch Wide thin fabrictape which has to be applied smoothly layer by layer with the turnsarranged to break joints. The wrapping also has to conform to certainelectrical characteristics with the result that the completed body isthickest in the center region and tapering therefrom toward .both ends.The amount of tape required rapidly increases with joints for higherpotential cables. Between the layers of tape, an insulating compound ofan oily nature is applied which further increases the labor of properlyapplying the tape, and makes the job a tedious one. Also the Work ofassembling numerous individual parts at the point of installationfurther increases the cost due to the extreme care with which theoperations must be performed.

The object of my invention is the provision of an improved .stop-joint.More specifically stated, one of the objects of my invention is the pro-Vision of a stop-joint, the principal insulating parts of which are madeat the factory in their final form and which may be readily assembled inplace at the point of installation with a minimum amount of hand Work onthe part of the splicer. A further object is the provision of astop-joint wherein the amount of hand Wound or applied tape is reducedto a small fraction of that customarily employed for joints of similarratings. A further object of my invention is an improved method ofmaking cable joints.

For a consideration of what I believe to be f novel and my invention,attention is directed to the accompanying description andthe claimsappended thereto.

In the accompanying drawings illustrating my invention, Fig. 1 is a viewof approximately onehalf of a stop-joint with certain of the parts 1nlongitudinal section; Fig. 2 is an enlarged View of the parts located atapproximately the center of the joint; Fig. 3 is a detail sectional viewtaken on line 3 3 of Fig. 2 showing how certain of the parts shown inFig. 2 are connected; Fig. 4 is a sectional view of the factory madecylinders which are assembled over the conductor ends; Fig. 5 is across-section taken on line 5-5 of Fig. 4 showing the oil grooves in oneofthe cylinders; Fig. 6 is a cross-sectional view of some of the factorymade barrier tubes which are assembled around the joint; Figfl is a sideview of a split ring for uniting parts of the connector, and Fig. 8 is adetail view showing the overlapping ends of the barrier tubes.

The necessary and desirable features of a stopjoint are (o) theprovision of suitable means for controlling the flow of insulatingliquid into and from the core of the cable; (b) the provision of meanswhereby the radial electric stresses to which the liquid is subjectedmay be controlled or conned within safe limits by a proper choice ofconductor and casing diameters, and (c) the provision of means wherebythe axial electrical stresses along the boundaries of the componentsolid insulations may be suitably controlled.

Approximately one-half of a joint is shown, the other half being aduplicate thereof. The complete joint is of the order of ninety-sixinches in length with a maximum diameter of eighteen inches.The'particular joint illustrated is intended for hollow core, leadsheathed cable operating at 230,000 volts. These ligures are givenmerely for the purpose of illustration and not as limitations of myinvention.

l, Fig. 2, indicates a part of one of the conductors having the usualfactory spirally applied paper insulation 8, the other conductor being a.duplicate thereof.` The conductor is of the stranded type having ahollow core 9 which is lled with `degasiiied liquid, such as oil, undersuper-atmospheric pressure. The oil passes through the spaces betweenstrands and impregnates the factory applied insulation 8. Toelectrically connect one cable length with the end of the next, adivided metal connector is provided, each part having a central bore I0and an annular socket ll in which the strands of the conductor 'l arelocated. The connector and the cable strands are united by exertingcompression pressure on the outer wall of the socket, as for example byindenting the connector wall by a suitable press and punch but othermeans may be employed for the purpose. To prevent the strands from beingpushed inwardly during the pressing operation and thereby reduce thesize of the oil channel in the core, a. strong metal tube I2 which maybe made of steel is provided. The connector is also provided with acollar I3 and a tubular extension I4, the latter being externallyscrew-threaded to receive a clamping nut I5, the latter having a sen'esof small angularly spaced recesses I9 to receive a spanner wrench. Theconnector also has one or more radial ports I4m for oil opening at theirouter ends into an annular space or chamber I1. Inside of the bore ofeach part of the connector is a valve I9 having exterior screw-threadsengaging similar threads in the wall of the bore. As shown, fthe valveis seated and hence the radial ports Il are shut oif from communicationwith the oil in the core of the cable. This position of the valve is atemporary one used`during assembly. Before the half connectors areunited, the valve will be moved, in this case to the right, to exposethe ports Il so that oil may freely pass between the conductor core andthe outside thereof. The valve in the other half connector will also bemoved to expose the oil port therein. Surrounding the connector part aretwo preformed factory made cylinders I9 and 20 which will be referred tolater. Located within the inner cylinder I9, Fig. 2, is a metal ring 2|which engages the collar I3 of a connector part. In the ring and in theinner cylinder are one or more radially disposed oil passages 22, inthis case two, which communicate at their inner ends with the annularspace or chamber I1, Fig. 2, and at their outer ends with oil groovesbetween the inner and outer cylinders I9 and 20. To unite the cylinderI9 and the ring, pins 23 are employed as shown in Fig.

. 3. These pins form a simple reliable means for uniting the parts butother means may be employed. The clamping nut I5 contacts with a sideface of the ring 2| and also with the end of the inner cylinder I9 tohold the parts in place, and to provide current carrying capacitybetween parts Il and 29. In other words, the arrangement of the partsdefinitely fixes the axial positions of the cylinders I9 and 29. Sincethere would be a tendency for oil or other liquid, especially whenheated, to pass from the cable into the joint' casing between the radialange of the nut and the cylinders I9 and 20, a compressible packing 24is provided and located in a cutaway portion of the flange near theperiphery thereof. The packing should be elastic and may be made of anoil resisting rubber or rubber-like compound'. It is of ring form and isheld against outward movement by the inner wall of the outer cylinder20. The nut I5 also has an externally screw-threaded part 25 to receivethe split clamping ring 29, Fig. 7, which electrically and mechanicallyconnects the two main halves or parts of the connector, it beingunderstood that each cable length has its halt connector.

A short portion of the factory applied insulation is removed to exposethe conductor end preparatory to connector attachment ln socket II.Insulation removal to a shouldered contour. as indicated in Fig. ,2, mayin some instances expedite the use of a connector attachment tool.

v'g Another portion of factory applied insulation is next removed toprovide contours adapted to electrical stress control. As indicated inFig. l, the removal leaves the remaining cable insulation with twoappropriately tapered surfaces converging to approximately the conductordiameter. The tapered or cored surface 28 is vthen overlaid withmetallic shielding braid 29 forming a stress cone to enforce a desiredstressing of the insulation.

Finally, tape is applied in firmly drawn wrappings over the attachedconnector, the assembled braid, and the exposed paper insulation in theregions 28 and 31. This tape should be wrapped to a smooth cylindricalsurface having the diameter of the original cable paper.

The tape insulation should be of such material that it does notappreciably degenerate under heat from any cause. As an example, thetape may be made of fabric coated or impregnated with a binder made ofvarnish or other suitable material. By reason of the steppedconstruction and the adjacent cone covered by metallic braid 29, theelectrical stress within the joint is reduced to the equivalent of aconductor of the diameter of the flanged nut. In this connection, itwill be noted that instead of removing all of the factory appliedinsulation from the ends of the cables which are to be jointed, as isthe customary practice, only a portion thereof spaced from the conductorend is removed and that by this procedure the benefit of the superiorfactory applied insulation on the extreme ends is retained. As will beseen from the drawings and particularly Fig. l, the removal of thefactory insulation results in the formation of double opposed cones, onetapering from the outside diameter of the insulation to the conductorand the other tapering in the opposite direction from the conductor tothe outside diameter of the factory insulation.

Instead of using a single preformed conical insulator over eachconductor end in accordance with prior practice, which insulators arerelatively diillcult to make and require special apparatus inltheirmanufacture, cylinders I9 and 20 are employed arranged in telescopicrelation and friction fitted one inside of the other. They are madev ofsheets of paper or equivalent material and wound on suitable cylindricalmandrels or rolls, one or more of which are or may be heated. l

The sheets are coated or impregnated with a binding material of whichcondensation products are examples. The binder may be applied in liquidform or as a dry powder. The paper as it is wound is desirably subjectedto heat and pressure with the ultimate effect of making hard densecylinders of high dielectric strength. In one or both of the cylindersthus formed are channels or grooves 39, Figs. 4 and 5, which serve toconvey oil between the core of the conductor and an outside source ofsupply. as for example through the fitting 3I mounted on an end of theenclosing metal casing. As it is a simpler machine operation to form thegrooves on an outside surface than on an inside, they are formed on theinner cylinder I9. The inner ends of the grooves communicate with theradial passages 22, Fig. 2, the inner ends of which are in comat one endby the collar I3 of a connector member and thereby maintained inconcentric relation with respect to the axis of the conductor. The outercylinder is internally supported by the flanged part of a connectormember.

In order to control the electrical gradients, the ends of the innercylinder I9 have incorporated therein a conducting material which maytake different forms. In the present instance, the edges of the paper ofwhich the cylinder is composed before winding are metalized by a coat ofso-called resistance paint in such manner that when wound, the metalizedparts appear in longitudinal section in the form of cones, the outersurfaces of which are indicated by lines 32 and 33, Fig. 1. In actualpractice, the cones when viewed in section are distinguished from themain body by a difference in color. It will be noted that line 33 denesa cone and is a continuation of the cone formed by the shielding braid29. It will also be noted that the braid 29 is at the potential of theconductor, that the braid and the metalized part of cylinder I9 are incontact at their point of meeting and that the outer or enlarged part ofthe cone dened by the contained metal is in electrical contact with thecollar I3 of the connector, ring 2I and part I5 and hence at the samepotential as the conductor and the braid. In this manner, an effectivegradient is provided extending longitudinally of the joint. Aspreviously stated, the parts of the joint on opposite sides of thecenter are alike. An advantage of this construction resides in the factthat the resistance paint is largely or wholly forced into the materialof which the cylinders are composed so that the inner and outerdiameters of the cylinders remain unchanged with respect to the mainbody thereof.

To avoid hand work on the part of the jointer or splicer as fully aspossible, the preformed inner and outer cylinders are properly fittedone inside of the other at the factory and desirably with a close t soas to preserve the desired concentric and axial relationship. Inaddition to this, the

" sections 34 and 35 of the metallic joint casing are pressure tted atthe factory over the inner and outer cylinders so that in effect theyform a unitary structure, and handled as such by the splicers. After theconductor insulation is stepped, the part 28 shaped to form a cone, thebraid 29 applied, the connector secured to the conductor, and thereinforcing bodies of tape insulation in regions 28a and 31 applied, thecylinders I9 and 20 are slipped endwise into place after which theclamping nut I of each half connector is screwed into place. Mention hasbeen made of first forming the double cone and then cutting away the endof the insulation to receive the connector, but these operations may bereversed, i. e. the ends prepared iirst. It will be noted that thegrooves 30 between the cylinders extend into the end part 34 of thecasing and that the inner cylinder I9 is somewhat smaller in diameternear its outer end than the casing as indicated at 38, thereby formingan annular space or chamber which communicates with all of the grooves30. The fitting 3l also opens into the chamber. A reservoir or othersource of supply under superatmospheric pressure is or may be connectedto the tting to receive oil or other insulating liquid as it heats andreturn it as the cable cools.

In order to separate the oil contained in the conductors from thatcontained in the main or central part of the enclosing joint casing andalso to prevent oil from one cable length flowing into the other throughthe joint casing, a shoulder 39 is provided between the end sections 34and 35 of the casing, best shown in Fig. 4, and at this point is locateda ring packing 40 which engages the shoulder on one side and the end ofthe outer cylinder 2|! on the other. When the cylinders are pressuretted into the metallic casing sections 34 and 35, the packing iscompressed and held in that condition by the pressure tting of theparts. After the inner and outer cylinders I9 and 20 are mounted inplace, the nut 25 seated and the split ring 25 mounted in place to unitethe halves of the connector, a body of insulation 26a composed of asmall amount of tape is wound in layers over the split ring and over theadjacent ends of the outer cylinder 2U, of which only one is shown inthe drawings. At some time previous to applying the split ring 26, thevalves I 8 are moved suiflciently to permit communication between thecable cores, the ports I4EL and grooves 30.

In order to further and properly insulate the` parts thus far describedfrom the metal joint casing, numerous concentric barrier tubes 4Iarranged in spaced relation are provided. The concentric spacedarrangement of the tubes is maintained by a series of insulating blocks42 arranged at suitable angularly spaced intervals. The blocks havesmall notches 43, Figs. l and 6, to receive a binding band 43a made ofinsulating cord to hold them in their respective positions. As will benoted, the inner tubes are the longest and gradually decrease in lengthto the outer one. Since the greatest stresses are near the Center of thejoint in planes transverse to the connector, a portion of the barriertubes of the left-hand part of the joint overlap portions of the barriertubes of the right-hand part as best shown in Fig. 8. In other words,the end portions of the barrier tubes are in telescopic relation. Thebarrier tubes may advantageously be made in the same manner as thecylinders I9 and 20 but they are of much thinner section.

Reference has previously been made to the end parts or sections of themetallic casing for the joint. The main or central part of the casingcomprises two cylindrical members 45 arranged end to end, the outerparts 46 connected thereto are cone shaped and conform generally inshape to the arrangement of the ends of the barrier tubes. The outerends of the parts 45 are wipe soldered at 41 to the end sections whichcarry the cylinders I9 and 2D and the end sections in turn are wipesoldered to the metallic cable sheaths as at 48.

Between the metallic casing members 45 is located a sheath insulator 49made of a good grade of insulating material adapted to withstand withoutinjury the effects of the oil within the casing and that of theatmosphere with which the joint is surrounded. To secure the insulatorin place, the halves of the main casing are provided with circularflanges 50 through which securing means such as bolts or studs extendinto or from the insulator.

The casing is provided with a tting 5I through whichinsulating liquidsuch as oil may be introduced into the casing to improve the insulatingeffects of the assembly. As previously indicated, this liquid is notpermitted to enter thecable core due to the presence of packings 24,Fig. 2, and 40, Fig. 4, and may or may not be degasied. Insulating oilwill withstand an electrical stress equal to approximately one-half thatof a cylinder of equal thickness made of paper and a binder or varnishedcloth tape. For this reason, the oil in the region where it emerges fromthe connector and enters the dielectric field requires a contacted metaldiameter of approximately five inches for stresses existing in'a 230,000volt joint. In the region of the cable connector where the diameter isapproximately one inch, oil would be overstressed, therefore varnishedcloth tape or equivalent material has to be used.

Electrical stresses imposed upon the boundary surfaces of two adjacentinsulations in the dielectric depend upon the variation in conductor andenclosing casing diameters. In the present instance, the conductordiameter varies from approximately one inch to five inches, the latterbeing the diameter of the flanged nut I5. Conductor sections representedby these two extreme diameters should therefore vbe separated by elevento twelve inches. A part of this length is obtained in effect by thecylinders I9 and 20,

and the remainder is accomplished by the braid covering 29 over thefactory applied insulation on the stranded conductor ends.

The combination of the coned surface of the factory applied insulationwith the metallic braid covering 29 and the metallization of the innerend of the tube I9 as indicated by the line 33, Fig. 1, gives in effecta gradual change from one inch diameter of the cable conductor to thefive inch diameter of the connector. The final effect is the same as ifthe metal connector and the end portion of the cylinder I9 under theline 33 were united in one solid mass of metal.

Among other advantages of my improved joint are the following:

(a) The use of the two factory made cylinders I9 and 2|), which arepressure fitted into parts of the casing with oil channels between,results in a material decrease in the amount of hand labor the jointeror splicer has to perform at the place of installation, usually amanhole below the level of the street. Being machine made in thefactory, Where the conditions are of the best, the insulation is moreeffective than when made by hand by a jointer, even under the best ofconditions. There is also a substantial saving in cost.

(b) The use of conducting material in the ends of the cylinders providesadequate control of the electrical gradients axially along the joint.

(c) A very great reduction in the amount of reinforcing tape requiredand hence decreased initial cost and a great saving of labor on the partof the jointer, as compared with previous designs for the same voltagesand types of service. The saving in tape and the labor of applying it isevident from the fact that the only bodies of tape required are thoseimmediately around and adjacent the connector. In the joint hereinillustrated for 230,000 volts, only about seven pounds of tape arerequired against about thirty pounds for a 138,000 volt joint of theprevious design. A joint for 230,000 volts made in accordance with theprior common practice would require about forty-five pounds orapproximately twenty-three hundred yards.

(d) The arrangement of the sheath insulator means that it can beinstalled by the jointer instead of being made an integral part of thejoint casing, thereby making the joint easier to assemble.

(e) The fact that all the wipe joints are located at places where thediameters are small results in a saving of labor and means lesslikellhood of faulty workmanship.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. A stop joint for fluid filled cables comprising insulated conductors,at least one of which has a fluid containing hollow core, a means forelectrically connecting the conductors and preventing the passage offluid from one conductor to another, a pair of preformed insulatingcylinders arranged in close fitting telescopic relation surrounding aconductor, a fluid flow channel of relatively small cross-sectional arealocated between the cylinders which at one end is in communication withthe core of a conductor, a casing part into which the outer ends of thecylinders are permanently secured, there being a chamber in the casingpart in communication with the outer end of the channel, a wrapping oftape around the connecting means and a part of the outer cylinder,concentric barrier tubes surrounding the cylinders and held in spacedrelation, and a casing surrounding the barrier tubes and connected atits ends to the casing parts in which ends of the cylinder are located.

2. A stop joint for fluid filled cables comprising a pair of insulatedconductors each having a hollow core, a separately maintained body offluid insulation in each of the cores, metallic connector membersuniting the conductors electrically and mechanically and preventing thepassage of fluid from one core to another, there being individual portstherein, pairs of cylinders made of dense insulating material in closefitting concentric arrangement, the inner cylinder of each pair beingfitted over the insulation on one of the conductors, a casing having endportions in each of which ends of the cylinders are seated, each of theportions having a chamber, and a central portion connected to the endportions, a channel between each pair of insulating cylinders forconveying fluid from the core of an enclosed conductor to a chamber inthe casing, barrier tubes in concentric spaced relation surrounding themajor portion of the lengths of the cylinders and enclosed by thecasing, and a filling of fluid for the portion of the casing enclosingthe barrier tubes.

3. A stop joint for fluid filled cables comprising a pair of insulatedconductors each having a hollow core, a separately maintained body offluid insulation in each of the cores, a connector for the conductorends comprising a member fitted to each of the conductors, each memberhaving an outwardly opening port communicating with a conductor core,and a means for electrically and mechanically uniting the members, pairsof concentric cylinders of hard dense insulating material, each pairenclosing an end of an insulated conductor, channels between each pairof cylinders communicating with a port at one end, means preventing thepassage of liquid from one conductor core to the other, a casing for thecylinders having end chambers with which the outer ends of the channelsare in free communication, concentric barrier tubes in spaced ,irelationsurrounding the connector and adjacent' ends of the insulatedconductors, and a fluid lling for the part of the casing enclosing thebarrier tubes.

4. An article of manufacture for cable joints comprising a pair ofpreformed cylinders, each made of wrapped dense insulating material anda binder, and arranged in telescopic relation and so maintained bymutual frictional engagement, both ends of the inner cylinder containingconducting material arranged to define stress cones diverging from thebore of the cylinder to the periphery thereof, a channel for fluidformed between the cylinders, a metallic casing element surrounding theouter end of the inner cylinder and pressure fitted thereto, a part ofthe casing and cylinder defining a chamber communicating with thechannel, a second metallic casing element secured to the first near oneend thereof and tightly fitted over an end of the outer cylinder toprevent the passage of fluid into the channel and chamber, the cylindersand casing elements forming a unitary structure applicable as such to acable end.

5. A stop joint for Iiuid filled cables comprising a pair of conductorshaving hollow cores, factory applied insulation on the conductors havingtapered surfaces in spaced relation to the adjacent conductor ends, aseparately maintained body of uid insulation in each of the cores, ametallic connector part for each conductor, a winding of tape insulationcovering the tapered surface of each conductor insulation, a metalliccovering for a part of the tapered surface of the factory insulation tocontrol the electrical gradient in that region, a pair of concentricinsulating cylinders enclosing an end of each conductor and the tapewinding thereon, each inner cylinder containing conducting material atits inner end forming a continuation of one of the metallic coverings inelectrical contact with the metal connector to form a shield, concentricbarrier tubes surrounding the connector and the major portion of thelength of the cylinders, a casing surrounding the cylinders and tubes,and a lling of liquid insulation for the casing.

6. In a stop joint for hollow core uid filled cables, a connector parthaving a collar and a screw-threaded extension, a pair of preformedtelescopic snugly tted cylinders of insulation surrounding a cable end,the inner cylinder being internally supported at one end by the collar,a nut mounted on the extension having a radially disposed face engagingan end of the inner cylinder and also forming an inside support for theouter cylinder, a channel for uid between the cylinders, a radial portextending through the inner cylinder into the channel, and a supportingcasing part for the outer ends of the cylinders containing a chamberwith which the outer end of the channel communicates.

'7. An article of manufacture for a part of a uid stop joint for cablescomprising a pair of preformed cylinders of hard dense insulatingmaterial arranged in snug tting telescopic relation, the outer cylinderbeing shorter than the inner cylinder and defining a shoulder, a channelformed in the inner cylinder of considerable length and smallcross-sectional area, a casing having parts of different diameters witha shoulder between, the part of smaller diameter surrounding the outerend of the inner cylinder and that of larger diameter engaging the outercylinder, and a packing located at the end of the outer cylinder andbetween it and the casing shoulder, the cylinders being rigidly fittedinto the casing parts to form a unitary structure therewith.

8. A stop joint for iiuid filled cables having a connector part, acollar, a screw-threaded extension, a nut on the extension, a pair ofpreformed cylinders of dense insulation tted one inside of the otherwith a fluid conveying channel between, the inner cylinder beingsupported from the inside by the collar and the outer cylinder beingsupported from the inside by the peripheral surface of the nut, a radialport for uid in the inner cylinder opening into the channel, and apacking located between a side surface of the nut and an end ofthe'inner cylinder and held against radial expansion by the inner wallof the outer cylinder.

9. A stop joint for hollow core cables comprising connector means forthe conductors, pairs of preformed cylinders of insulation, those ofeach pair being in telescopic relation between which fluid is permittedto flow, an end casing part initially and permanently secured to theouter ends of both cylinders of each pair, the cylinders of each pairenclosing a conductor end and engaging the connector means in a mannerto prevent iow of iiuid from one cable to another, each pair ofcylinders and a casing part forming a unitary structure and assembled inthe joint as such, a series of concentric tubular barriers surroundingthe central part of the joint and extending from the ends of the jointto points beyond the center thereof, the adjacent ends of the tubesbeing in overlapping relation, a central casing for the joint attachedat its ends to the said end casing parts, and a filling of liquidinsulation for the part of the casing containing the tubes.

10. In a cable joint, conductors arranged end to end, factory appliedinsulation on each of the conductors which isl cut away to form a pairof opposed cones, the latter being in spaced relation to the conductorend, electrical conducting means applied to one of the cone surfaces toform a stress cone, a covering of wrapped on insulating tape filling thespace defined by the cones having a diameter substantially equal to thatof the factory insulation, a preformed cylinder of dense insulatingmaterial for each conductor having parallel walls surrounding thefactory insulation andthe winding of tape, the inner end of the cylinderbeing metalized to form a continuation of the stress cone, metallicsheaths for the insulated conductors, connector means electricallyuniting the conductors and also supporting the inner ends of thecylinders, and a metallic chamber casing comprising end portions jointedto the sheaths, each end portion and a cylinder being united so as toform a unitary structure and applied as such over a cable end, and acentral portion connecting the end portions and with them forming acomplete enclosure for the joint, the chamber containing insulatingfluid.

11. In a cable joint, conductors arranged end to end, each having afluid lled hollow core, factory applied insulation on each of theconductors which is cut away in spaced relation to the end of theconductor to form a coned shaped surface diverging from the conductortoward the center of the joint, electrical conducting means covering thesurface to form a stress cone, a covering of wrapped on insulating tapefor the stress cone which fills the space defined thereby tosubstantially the same diameter as that of the factory insulation, apair of telescoped cylinders made of dense insulating materialsurrounding the factory insulation and the winding of tape on eachconductor, a conduit of restricted cross-sectional area located betweenthe cylinders of each pair of cylinders and extending lengthwisethereof, said conduit communicating with the core of a conductor,connector means uniting the conductors and also engaging and acting assupports for the inner ends of the cylinders, and

with them preventing free flow of fluid between a conductor core and thejoint casing, a chambered joint casing comprising end portions in eachof which is located and secured the outerl ends of a pair of cylindersto form a unitary structure and a central portion united with the endportions to complete the casing, and a filling of insulation for thechamber.

12. In a cable joint, insulated metallic sheathed hollow coreconductors, a filling of insulating fluid for each of the cores, aconnector means attached to the conductors for electrically uniting themand preventing the fiow of fluid from one core to the other, preformedcylinders of insulating material arranged in fixed telescopic relationsurrounding an insulated end of each of the conductors, a fluidcontaining channel 1ocated between the respective cylinders andcommunicating at its inner end with the core of a conductor, a metalliccasing comprising end portions sealed one to each metallic sheath, eachportion having a chamber at its outer end communicating with thechannel, the cylinders being permanently secured in the end portions toform unitary structures, a fitting carried by each end portion throughwhich fluid may flow into and from the chamber, and a central portionsealed at its outer ends to the adjacent end portions for connectingthem to form a complete enclosure for the joint.

13. In a high tension cable joint, a conductor, factory appliedinsulation thereon which is removed near an end thereof to form a pairof cones with their small ends adjacent, a metal covering for one of thecones, a body of tape wrapped over the cones and the metal covering to adiameter substantially equal to that of the original factory insulation,a preformed cylinder of dense insulation having high dielectric strengthsurrounding the body of tape and also the adjacent portions of thefactory insulation, conducting material incorporated in an end of thecylinder and defining an outwardly diverglng cone which in effect formsa continuation of the metal covered cone of the factory appliedinsulation, a metal sheath for the insulated conductor, and an enclosingmetal casing which is sealed to the sheath.

14. In a joint for high tension cables, conductors, factory appliedinsulation on each of the conductors, a portion of which is removed toform an end shoulder and expose a short length of conductor, and asecond portion also removed to define a conical surface longitudinallydisplaced from the shoulder, a stress cone surrounding the conicalsurface and mounted thereon, a connector member for each conductorhaving a collar and socket to receive the exposed length of conductor, abody of tape wrapped around each socket and filling the space betweenthe shoulder and collar and having a diameter approximating that of thecollar, a second body of tape covering the stress cone and having adiameter approximating that of the factory insulation, a preformedcylinder of hard dense insulating material coveringa portion of thefactory insulation and also the bodies of tape, a means carried by aconnector member engaging the wall of the cylinder at its inner end forsupporting-it, and a chamber enclosing a casing for the joint containinginsulating fluid comprising central and end portions, each of the endportions surrounding and engaging the outer end of a cylinder forsupporting it.

15. 'I'he method of connecting high potential insulated sheathedconductors which comprises cutting away the factory applied insulationon each of the conductors in spaced relation to the end thereof in amanner to denne a cone, removing the factory applied insulation at theadjacent ends of the conductors to expose the metal conductors, securingconnecting means to the conductors to unite them, applying a metalcovering to each cone of insulation nearest the connecting means,covering the cutaway portions of the insulation of both conductors withinsulating tapes to approximately the diameter of the factory appliedinsulation, applying insulating cylinders having metalized ends over theinsulating tapes with the metalized portions forming continuations ofthe metal coverings on the cone of the factory applied insulations.applying a covering of insulation over the connector means, enclosingthe joint thus formed with a metallic casing, and securing the ends ofthe casing to the sheaths of the conductors.

16. The method of connecting high potential insulated metal sheathedconductors which comprises cutting away the factory applied insulationon each of the conductors in a region located in spaced relation to therespective ends thereof to a depth to expose the conductors and formdouble cones with their small ends adjacent each other, wrapping a thinmetallic covering over the cones nearest to the ends of the conductors,wrapping the coned surfaces and the metallic coverings with insulatingtapes to the approximate diameter of the factory applied insulation,applying cylinders of insulation having metalized ends over theinsulating tapes with the metalized ends forming continuations of themetallic coverings, cutting away the insulation adjacent the ends of theconductors to expose them, applying connecting means to the conductorends for electrically uniting them, applying insulation over theconnecting means, surrounding the central part of the joint thus formedwith cylinders of insulation, enclosing the parts in a metallic casing,and securing the casing to the sheaths of the conductors.

17. In a cable joint, a conductor, factory applied insulation thereon, aportion of which is removed to form a conical surface, a metalliccovering for the conical surface forming a stress cone, a cylinder ofhard dense insulating material surrounding the insulation on theconductor and also the stress cone, and metallic material arranged todefine a cone incorporated in the end of the cylinder immediatelysurrounding the stress cone and positioned to form a continuationthereof.

18. In a cable joint, a conductor, factory applied insulation thereon, aportion of which is removed to form a conical surface, a metalliccovering for the conical surface forming a stress cone, a cylinder ofhard dense insulating material closely surrounding the insulation on theconductor and also the stress cone, and metallic material incorporatedin both ends of the cylinder arranged to define cones, that in the outerend diverging outwardly from the factory applied insulation rargl/thaton the inner end immediately surrounding the stress cone and positionedto form a continuation thereof.

LESTER L. PHILLIPS.

